TV-Series
Description
This supporting character, credited solely as Trainer, develops Team Spica's horse girls. He displays a generally carefree and impulsive nature, often seeming sloppy at his duties while maintaining a professional rivalry with colleague Hana Toujou. His training philosophy prioritizes trusting his pupils' instincts, encouraging them to run freely rather than enforcing rigid strategies, though he enforces firm expectations during practice. A recurring habit involves gauging new horse girls' running potential by feeling their thigh muscles, frequently causing misunderstandings that result in him being kicked. He exhibits financial irresponsibility, routinely borrowing money from Hana to cover unpaid bar tabs or meals.

Physically, he appears as a carefree man with tanned skin. His brown hair is messy, styled in a short ponytail combined with a left-side undercut, and he has small amber eyes. He is consistently depicted chewing on a lollipop stick and sporting light facial stubble. His standard attire includes a yellow button-up shirt beneath an unbuttoned black waistcoat, long black pants secured by a white belt with a gold buckle, and plum-colored leather shoes. His height is 180cm.

Relationships are central to his role. His dynamic with Hana Toujou mixes professional rivalry and reliance, as he frequently depends on her financially despite her clear romantic interest, which he dismisses or overlooks. Among the horse girls, Gold Ship shares the longest association; he shows familiarity with her unpredictable behavior, sometimes assigning unconventional training routines unrelated to running. He maintains close, grounding relationships with Daiwa Scarlet and Vodka, helping manage their competitive streaks. Initial interactions with Special Week were distrustful due to his assessment methods, but through consistent support, he gradually earned her respect, becoming a trusted emotional anchor for all Team Spica members.

His narrative role significantly evolves during Season 2 in response to Tokai Teio's storyline. After Teio sustains injuries winning the Japanese Derby and faces difficult rehabilitation before the Kikkashou race, he guides her to seek perspective from Symboli Rudolf following her subsequent defeat. His support proves crucial during her toughest period; learning of her planned withdrawal from Team Spica after fracturing a bone for the third time and facing potential permanent speed loss, he intervenes. He persuades her to race one final time for her fans, facilitating her emotional recovery and return to training. He remains actively involved in her preparation for the Arima Kinen race, closely observing her progress.

Supplementary materials and fan communities refer to him as "Okino Trainer" (derived from his voice actor's surname) and "Ryo Nishizaki" (a name appearing in official first-season anime setting materials). His visual design bears a noted resemblance to actor Yo Oizumi, who has appeared in Japan Racing Association (JRA) campaigns.